Issue with Westinghouse 19" LCD Monitor (large pics)

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

I'm concerned about these. These sizes might need to be low-ESR caps, and Nichicon KT series don't appear to be low ESR.
Do they have these in the Nichicon HE? That would be a better choice.

Saw the first two and the last two full desc, never saw the Audio grade in the middle. Also, providing the series gives PC (and others around the forum) the data he needs to make a very specific suggestion. See? the more data you give in, the more data you get out.

[gdement]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

3x 25V 220μF (KF)
2x 25V 1000μF (KF)
1x 10V 2200μF (KF)
1x 10V 1000μF (KF)
1x 50V 47μF (GL)
1x 50V 22μF (GL)

1x 400V 100μF (KM)

This is all still pretty new to me. I know low ESR is where I want to go, and I even see the parts list for Nichicon high-to-low ESR, I just didn't find my particular caps listed...maybe that's because they were too high of ESR. I'll do some more searching

Nichicon HE is a good replacement for all of those (excluding the big 400V cap).
But Nichicon HE doesn't come in 47uF. Maybe they have 47uF Chemicon KY, which are the same specs as HE. Or maybe you could use a 56uF, I don't know if that's safe or not.

Don't use the Nichicon VY on the smaller ones - they aren't good enough to meet the old specs.


I found the CapXon datasheets here:
http://www.capxongroup.com/en/prod_all_cat_full.aspx
Nichicon HE can be found here:
http://www.nichicon-us.com/english/p...ini/list_f.htm
direct link:

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Alright, here is what I have planned in my cart now:

Mouser #: 647-UPW1E102MHD
Mfr. #: UPW1E102MHD
Desc.: Low Impedance Radial Aluminum Electrolytic Capacitors - 105Degree 1000uF 25V 105c 12.5x20 20% 5LS

Mouser #: 647-UHD1A222MHD
Mfr. #: UHD1A222MHD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 2200uF 10V 105c 12.5x20 20% 5LS

Mouser #: 661-ELXZ500ELL470MFB
Mfr. #: ELXZ500ELL470MFB5D
Desc.: Radial Aluminum Electrolytic Capacitors 50volts 47uF 6.3X11.5

Mouser #: 647-UHE1H220MDD
Mfr. #: UHE1H220MDD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 22uF 50V 105c 5x11 20% 2LS

Mouser #: 647-UHE1A102MPD
Mfr. #: UHE1A102MPD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 1000uF 10V 105c 8x20 20% 3.5LS

Mouser #: 647-UPTW6101MHD
Mfr. #: UPTW6101MHD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 100uF 420V 18X35.5 20%

Mouser #: 647-UHE1E221MPD
Mfr. #: UHE1E221MPD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 220uF 25V 105c 8x11.5 20% 3.5LS


I went HE where I could, went with a PT for the 420V/100uF, PW for another, and HD for yet another. I think this fits what everyone has been telling me. I'll leave this up overnight and make the order sometime tomorrow afternoon unless someone has an issue.

EDIT: Oh, and yes, I did get to sizing these things up. I have a limit on height of 25mm, with the exception of the 420V cap, which will be on its side.

Thanks!

Collin

[PCBONEZ]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Audio grade is fine for PC use.
In most cases the only difference is the material of the leads [often copper w/tin plating] and that they etch the foil differently before forming the oxide layer on it.
It helps in Audio apps and doesn't hurt in other apps.

Yes HE probably exceeds the minimum required for all of theses.
I see no reason they couldn't be used, just not what I usually use.

~~~ Now that list I can work with ~~~

FC is a close match to KF
- In some the FC is smaller cap than the same uF/volt in KF and in those cases FC may be rated less than KF.
- Only affects the 2200uF/10v in this particular list.

GL are better than FC in those sizes.

The KM is a general purpose cap with 560 mA for ripple rating.

KF_______

25V 220μF 8mm (KF) 550/.150
-- FC [8x11.5 mm] EEUFC1E221, 555/.117

25V 1000μF 13mm (KF) 1650/.045
-- FC [12.5x20 mm] EEUFC1E102, 1655/.038

10V 2200μF 13x20 mm (KF) 1750/.041
-- FC [10x30 mm] EEUFC1A222L 1815/.035 [Recommend FC if not too tall]
-- FC ~16v~ [12.5x25 mm] EEUFC1C222 1945/.030 [A viable alternate if 25mm fits]
-- HE [12.5x20 mm] UHE1A222MHD6 1900/.035

10V 1000μF 10mm (KF) 1040/.076
-- FC [10x16 mm] EEUFC1A102, 1050/.068

GL_______

50V 47μF 8mm (GL) 285/.500 [FC, doesn't have a good match]
-- Nichicon PW 6.3x11 mm 300/.430

50V 22μF 6.3mm (GL) 135/1.00 [FC, doesn't have a good match]
-- Chemicon LXZ 5x11.5 mm 155/.900

KM_______

400V 100μF 18x35.5 mm (KM) 560mA at 120Hz
--- Chemicon KXG 18x31.5 mm -- 765mA at 120Hz

..

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Thanks to everyone for their input; the order to Mouser has been made. Keep your fingers crossed.

I have the replacement MOSFETs coming in either today or tomorrow. I have to think of a good way to get those things in without burning the board or the MOSFETs themselves. Probably will try to use an alligator clip when soldering leads into place.

Anyone care to speculate on whether I should test the board after new MOSFETs are in place or should I wait for the recap job before plugging anything in?

Thanks again to everyone!

Mobaar

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Thanks to everyone for their input; the order to Mouser has been made. Keep your fingers crossed.

I have the replacement MOSFETs coming in either today or tomorrow. I have to think of a good way to get those things in without burning the board or the MOSFETs themselves. Probably will try to use an alligator clip when soldering leads into place.

Anyone care to speculate on whether I should test the board after new MOSFETs are in place or should I wait for the recap job before plugging anything in?

Thanks again to everyone!

Mobaar

I went ahead and ordered them too.
I have recapped it already. I guess it would be wise that you do it too before installing the new pair.

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Ugh, I'm finished but no dice on the backlight working.

I've checked and double-checked capacitor polarity, made sure there weren't any shorts in the system or any solder crossover, but it's behaving exactly like it did last time.

The MOSFET replacements checked out on a multimeter before I put them in, and it looks like everything is squared away. When I turn the monitor on, the backlight doesn't turn on; on the bright side (so to speak) there don't appear to be any overheating or shorting out parts.

Is there anything I'm overlooking? It seems like something is just keeping the voltage from getting to those backlights. Maybe I can rig something to supply the power alternatively, but I really was hoping to get this fixed the old fashioned way.

Any tips or advice? I can't seem to find any inconsistencies in the circuit. Heck I'm willing to pay someone a little something if they'd be willing to look things over and diagnose it. Or maybe someone can walk me through how to diagnose where the issue is coming from.

Collin

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Ugh, I'm finished but no dice on the backlight working.

I've checked and double-checked capacitor polarity, made sure there weren't any shorts in the system or any solder crossover, but it's behaving exactly like it did last time.

The MOSFET replacements checked out on a multimeter before I put them in, and it looks like everything is squared away. When I turn the monitor on, the backlight doesn't turn on; on the bright side (so to speak) there don't appear to be any overheating or shorting out parts.

Is there anything I'm overlooking? It seems like something is just keeping the voltage from getting to those backlights. Maybe I can rig something to supply the power alternatively, but I really was hoping to get this fixed the old fashioned way.

Any tips or advice? I can't seem to find any inconsistencies in the circuit. Heck I'm willing to pay someone a little something if they'd be willing to look things over and diagnose it. Or maybe someone can walk me through how to diagnose where the issue is coming from.

Collin

Since we have the same board, same problem, but just different LCD size (mine is 20.1", yours is 19"), I guess I can help. I'm about to pull that box in front of the line, so I can get it and see what can I suggest.
Here's a picture of my board, that is discussed on another thread :


Give me a couple of hours and I'll be back with you. Too bad that my MOSFETS have not arrived yet .....

[anno]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

find a IC in inverter area that handles the backlight. find a datasheet and look for the voltage supply pin (vcc). Check if the vcc pin of the IC is getting voltage (around 12-18 volt). If there is no voltage trace back in the circuit. maybe there is an open fuse or the "backlight on" signal is missing from mainboard (bad mainboard)

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Well the CCFL inverter IC is a BIT3713, a 16-pin IC. Trying to find the datasheet on it now.

Collin

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Moobar, I have some questions for you.
But before, let me tell you that I had to make a quick trip to Mexicali (at the border, in Mexico, where I used to live), and as I didn't receive the MOSFETS, I bought them there. They cost there, at the current exchange rate, $1.20 USD. I bought two, and as soon I arrived home I installed them, and now I am typing using my newly repaired 20.1" Westinghouse. But I had the same problem as you : new MOSFETS in, same shit out : no backlight.
Before messing with the IC, look at this:

Right at the side of the MOSFETS, there's a jumper labeled J204.
I have 14v there, which I assume it is the voltage that feeds the inverter part of the board.If you don't have a V reading there, then move to the other side of the board.
There are small jumpers and fuses (SMD) there. The fuse highlighted was open in my board, so no voltage reached the MOSFETS. Replacing the fuse fixes the problem. Now I have image & backlight, but here's the question that you could answer me in case you fix yours too:
in the MOSFET at the left , I get the following readings :
S: 0.79v
D: 6.60v
G: 0v
In the MOSFET at the right, I get:
S: 6.54v
D: 14.06v
G: 4.14v

I replaced both of them, and after the readings, I switched them with each other. The readings remained the same (readings didn't move with the MOSFETS, so I guess they are not bad).
Any idea if this is normal, anyone?

[Scenic]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

no exact match... but it could help to find the correct pin..

http://www.alldatasheet.com/view.jsp...3713&q=BIT3713

edit: ^ see post above.. lol

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

no exact match... but it could help to find the correct pin..

http://www.alldatasheet.com/view.jsp...3713&q=BIT3713

edit: ^ see post above.. lol

Scenic, any idea if this readings are normal?

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

I am more than willing to look into this fuse issue like you are suggesting, but I have 2 very very elementary questions to ask (remember, I am new at this whole circuit board stuff!)

1.) I have my multimeter and I'm ready to take some DC readings with it. Red probe on the jumper in question, black probe where? Supposed to go to ground, but I want to make sure I'm doing everything exactly right before I go probing around on the PCB.

2.) How do I know if a circuit board fuse is "open?" Is this something visible or do I just do a quick continuity test?

Thanks again. I'll get on that tonight once I get some quick directions

Collin

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

I am more than willing to look into this fuse issue like you are suggesting, but I have 2 very very elementary questions to ask (remember, I am new at this whole circuit board stuff!)

1.) I have my multimeter and I'm ready to take some DC readings with it. Red probe on the jumper in question, black probe where? Supposed to go to ground, but I want to make sure I'm doing everything exactly right before I go probing around on the PCB.

2.) How do I know if a circuit board fuse is "open?" Is this something visible or do I just do a quick continuity test?

Thanks again. I'll get on that tonight once I get some quick directions

Collin

Red probe (+) on fuse, and black one (-) on GND. I first make the continuity test.
You can put the (+) on JP204 and the (-) on GND, and you should have a V reading (DC) if the fuse is OK.

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Right. Where *exactly* is GND? I've heard too many conflicting cases of where exactly that black probe is going. Sorry, it's really a very basic question.

Collin

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Right. Where *exactly* is GND? I've heard too many conflicting cases of where exactly that black probe is going. Sorry, it's really a very basic question.

Collin

No problem.
GrouND is any part of the metallic part of the chassis. You can put the probe in the screw hole right at the top of the barcode to the right. That's where I put the black probe when I was testing my LCD. That will serve to test on J204.

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Strange readings...

Some of the time the jumper gave me readings of 0, but other times it would read exactly .375V (or .4V or .38V, depending on the setting of the MM). Continuity of the fuse was nonexistant.

So if that proves that the problem is with that fuse...how in the world do I get one of those little things??? And how do I replace it? sheesh!

Collin

[EGuevarae]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Strange readings...

Some of the time the jumper gave me readings of 0, but other times it would read exactly .375V (or .4V or .38V, depending on the setting of the MM). Continuity of the fuse was nonexistant.

So if that proves that the problem is with that fuse...how in the world do I get one of those little things??? And how do I replace it? sheesh!

Collin

I got a variable ohms reading sometimes, and sometimes a complete open. What I did, while I can get a fuse, was bridge the two ends of it with solder, just to test. It is not recommended to do it, but that is what I did. you can do it just to see if that is your problem. And I will take the fuse from a dead board I have around here. Test it and then if that's your problem, we can ask someone to suggest a replacement fuse. I guess it opened/failed when the MOSFET shorted (it is the fuse that protects the Inverter). My unit has been operational for more than two hours, and is a nice screen, despite having one stuck pixel (green dot always on). I don't mind 1 in the middle of millions ....

[mobaar]

Re: Issue with Westinghouse 19" LCD Monitor (large pics)

Holy crap....it worked.